The present invention relates to a cruise controller for vehicles and, more particularly, to a controller which can perform vehicle-interval distance based F/B control.
An auto-cruise function includes vehicle-speed based F/B control for automatically maintaining the vehicle speed of the own vehicle to be a target vehicle speed set by a driver, and vehicle-interval distance based F/B control for maintaining the vehicle-interval distance to a vehicle ahead to be a distance set by the driver.
Many vehicles comprising such auto-cruise functions have been proposed.
For example, Japanese Patent Laid-Open No. 63-269736 discloses a cruise controller for vehicles having both the vehicle-speed based F/B control function and the vehicle-interval distance based F/B control function, wherein a control gain for the vehicle-interval distance based F/B control is changed in accordance with the traveling state in an auto-cruise mode, thus allowing quick convergence to a target vehicle-interval distance.
Japanese Patent Laid-Open No. 3-118700 discloses a cruise controller for vehicles having the vehicle-interval distance based F/B auto-cruise control function, wherein a target vehicle-interval distance is set in accordance with the coefficient of friction of a road surface.
Japanese Patent Laid-Open No. 61-150835 discloses a cruise controller for vehicles having both the vehicle-speed based F/B control function and the vehicle-interval distance based F/B control function, wherein the vehicle-speed based F/B control is executed based on previous vehicle speed data when the vehicle-interval distance cannot be detected.
Japanese Patent Laid-Open No. 61-6034 discloses a cruise controller for vehicles having the vehicle-speed based F/B control function, wherein a target vehicle speed during traveling on a curve of a road is set in correspondence with the curvature of the curve, so that a vehicle can travel on the curve at a proper target vehicle speed.
Furthermore, in a controller using the vehicle-speed based F/B control disclosed in Japanese Patent Laid-Open No. 58-29018, the acceleration of a vehicle in a normal driving state is detected, and is learned by storing acceleration data in correspondence with the acceleration generation frequency. This learning coincide an acceleration to be obtained when the vehicle-speed based F/B control mode is canceled to resume a normal traveling mode, or an acceleration to be obtained when the vehicle-speed based F/B control mode is resumed from the normal traveling mode with the acceleration feeling intended by a driver (i.e., the learned acceleration).
As described above, using the vehicle-interval distance based F/B control mode, a vehicle automatically performs speed control to maintain a target vehicle-interval distance. In this regard, the individuality of a driver is reflected in the target vehicle-interval distance, and the target vehicle-interval distance is often influenced by a driver's "habit" or "favor". More specifically, some drivers set relatively small vehicle-interval distances, and some other drivers set relatively large target vehicle-interval distance.
However, although the conventional auto-cruise controller variously changes a target vehicle-interval distance for the vehicle-interval distance F/B control, the target vehicle-interval distance is set in accordance with an external environment. Therefore, the target vehicle-interval distance set by the controller is not always one which matches with each of drivers.